Author: Hannon, F.E.
Paper Title Page
WEPWA077 Aperture Test for Internal Target Operation in the JLAB High-current ERL 2289
 
  • S. Zhang, S.V. Benson, G.H. Biallas, K. Blackburn, J.R. Boyce, D.B. Bullard, J.L. Coleman, J. Delk, D. Douglas, P. Evtushenko, C.W. Gould, J.G. Gubeli, F.E. Hannon, D. Hardy, C. Hernandez-Garcia, K. Jordan, J.M. Klopf, R.A. Legg, M. Marchlik, W. Moore, G. Neil, J. Powers, T. Powers, D.W. Sexton, M.D. Shinn, C. Tennant, R.L. Walker, G.P. Williams, F.G. Wilson
    JLAB, Newport News, Virginia, USA
  • J. Balewski, J. Bernauer, W. Bertozzi, R.F. Cowan, P.F. Fisher, E. Ihloff, A. Kelleher, R. Milner, L. Ou, B.A. Schmookler, C. Tschalär
    MIT, Middleton, Massachusetts, USA
  • N. Kalantarians
    Hampton University, Hampton, Virginia, USA
 
  Funding: Supported by the Commonwealth of Virginia, U.S. DOE Nuclear and High Energy Physics, and by the U.S. DOE Basic Energy Sciences under contract No. DE-AC05-060R23177.
A high current beam transmission test has been successfully completed at the JLAB FEL Facility, culminating in very low-loss transmission of a high current CW beam through a small aperture. The purpose of this test was to determine if an ERL is capable of meeting the stringent requirements imposed by the use of a 1018/cm3 internal gas target proposed for the DarkLight experiment*. Minimal beamline modifications were made to create a machine configuration that is substantially different from those used in routine UV or IR FEL operation. A sustained (8 hour) high power beam run was performed, with clean transmission through a 2 mm transverse aperture of 127 mm length simulating the target configuration. A beam size of 50 um (rms) was measured near the center of the aperture. Experimental data from a week-long test run consistently exhibited beam loss of only a few ppm on the aperture while running 4.5 mA current at 100 MeV – or nearly 0.5 MW beam power. This surpassed the users’ expectation and demonstrated a unique capability of an ERL for this type of experiments. This report presents a summary of the experiment, a brief overview of our activities, and outlines future plans.
References:
* P. Fisher, et al.,“Jlab PR-11-008: A Proposal for the DarkLight Experiment at the Jefferson Laboratory Free Electron Laser.” http://www.jlab.org/expprog/proposals/11prop.html
 
 
WEPWO073 RF Design Optimization for New Injector Cryounit at CEBAF 2471
 
  • H. Wang, G. Cheng, F.E. Hannon, A.S. Hofler, R. Kazimi, J.P. Preble, R.A. Rimmer
    JLAB, Newport News, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A new injector superconducting RF (SRF) cryounit with one new 2-cell, β=0.6 cavity plus one refurbished 7-cell, β=0.97, C100 style cavity has been re-designed and optimized for the engineering compatibility of existing module for CEBAF operation. The optimization of 2-cell cavity shape for longitudinal beam dynamic of acceleration from 200keV to 533keV and the minimization of transverse kick due to the waveguide couplers to less than 1 mrad have been considered. Operating at 1497MHz, two cavities has been designed into a same footprint of CEBAF original quarter cryomodule to deliver an injection beam energy of 5MeV in less than 0.27o rms bench length and a maximum energy spread of 5keV.